Method for forming metal wiring without metal byproducts that create bridge between metal wires in a semiconductor device

1. A method for forming a metal wiring, the method comprising the steps of: i) providing a semiconductor substrate formed with an insulation layer having a conductive plug; ii) forming a metal layer including first Ti/TiN layer, an Al layer, and a second Ti/TiN layer, which are sequentially deposited, on an entire surface of the semiconductor substrate; iii) successively forming a hard mask layer consisting of a TEOS layer and an anti-reflective layer on the metal layer; iv) forming a photosensitive film pattern having a predetermined shape on the anti-reflective layer such that the photosensitive film pattern covers at least the conductive plug and a part corresponding to the conductive plug; v) plasma etching the anti-reflective layer and the TEOS layer by using the photosensitive film pattern as a mask, thereby forming a patterned hard mask layer; vi) physical etching a portion of the metal layer and a surface of the insulation layer exposed due to the physical etching of the metal layer by using the patterned hard mask layer as an etching mask, thereby forming the metal wiring, wherein the bias power applied in the physical etching step is sufficiently increased to overetch the surface of the insulation layer such that any metal by-product left on the surface of the insulation layer is removed; and vii) removing the photosensitive film pattern.

2. The method as claimed in claim 1 , wherein the plasma etching step utilizes plasma having activated CHF 3 and CH 4 gases.

3. The method as claimed in claim 1 , wherein the physical etching step is carried out utilizing plasma including activated Cl 2 , BCl 3 , and N 2 gases.